1. Field of the Invention
This invention relates to seatbelt systems and more particularly to passive seatbelt systems which automatically fasten the belt around the passenger after the passenger has seated himself in the vehicle.
2. Prior Art
Seatbelt systems restrain passengers and prevent them from colliding with dangerous objects during a vehicular emergency. As a result, such systems contribute to the safety of the passenger. However, the percentage of the passengers who wear seatbelt is extremely low because of difficulty in donning the seatbelts, etc. As a result, various types of passive seatbelt systems have been proposed which make it possible to automatically fasten the belt around the passenger after the passenger has seated himself in the vehicle.
Among these systems, passive seatbelt systems which cause the belt to approach or move away from the seated passenger by using the driving force of a motor to move a runner piece which anchors the outer end of the passenger restraining belt are able to provide a reliable operation. The movement of the runner is guided by a guide rail which is fastened to the roof side member for door, etc., of the vehicle. During a vehicular emergency, the tension applied to the belt by the passenger is transmitted to the runner piece. Accordingly, this runner piece must reliably support the belt tension and transmit the tension to the vehicle body. However, in cases where a large, strong runner piece is used, the passenger space in the vehicle is decreased. In such arrangements, furthermore, the runner piece becomes a large projecting moving object inside the passenger compartment. As a result, the passenger is prevented from comfortably entering and exiting the vehicle.